Certain multibeam radar sensor apparatuses are used, for example, in proximity radar warning systems or adaptive cruise control systems of motor vehicles. For example, using a multibeam radar sensor apparatus, an adaptive cruise control system may be implemented which controls the vehicle speed as a function of the speed of other road users.
To increase the spatial resolution of the multibeam radar sensor apparatus, DE 10 2004 044 130 describes the use of a plurality of parallelly positioned antennas, which each emit and receive a radar beam or a radar beam lobe. In this context, the emitting and the reception of the reflected radar signal is accomplished by one and the same antenna.
In addition, further antennas may be provided whose transmitting capacity is reduced or whose transmitting capacity may be completely dispensed with. These purely receiving antennas are normally situated at the edge regions of a multibeam radar sensor apparatus, in order to produce narrower, inner radar beam lobes. In this manner, the angular resolution is further improved and the adjacent-lane interference is reduced.
However, the above-mentioned measures cannot prevent targets having a large backscatter cross section from also being, detected in an angular range that is outside of the visual range of the sensor. Consequently, the proximity radar warning system and/or adaptive cruise control system in the motor vehicle is also influenced by objects, which, for example, could be passed safely in an adjacent lane. Furthermore, the angular resolution of the known multibeam radar sensor apparatuses is often not sufficient for clearly identifying false echoes as such, which occur due to reflections at buildings or roadway boundaries, and for suppressing them. Because of this, individual objects are often detected multiple times at different visual angles. This also results in spurious signals in the case of proximity radar warning, or in unwanted reactions of an adaptive cruise control system.